fig1: Vespula spp and Apis mellifera venoms induce a preferential activation of CD1a-restricted T cells among the group1-CD1 reactive cells. (A) T cells were isolated by CD3 MACS beads from healthy donor PBMCs and cultured for 12–14 d with IL-2 and irradiated K562 cells transfected with CD1a (K562-CD1a), CD1b (K562-CD1b), CD1c (K562-CD1c), CD1d (K562-CD1d), or an empty vector (K562) in the presence of venom. CD1 reactivity was then examined by IFN-γ ELISpot with transfected or untransfected K562 cells either in the presence or absence of Vespula spp or Apis mellifera venoms. Representative data for one donor (C1175) of three are shown. (B) The CD1a-restricted T cell response in the presence or absence of anti-CD1a (donor C1098) and Vespula spp and Apis mellifera venoms. CD1a-restricted, venom-specific responses were measured in 21 donors for Vespula spp venom (C) and Apis mellifera venom (D). mDC or in vitro LC–like cells derived from CD14+ cells were pulsed with 1 µg/ml wasp venom (E) or bee venom (F) and incubated with the T cells in the presence or absence of anti-CD1a antibody or isotype control. IFN-γ production was measured by IFN-γ ELISpot. Representative data for one donor (C556 [E] and C560 [F]) of three are shown. Data were mean of triplicate measurements ± SEM. *, P < 0.05; **, P < 0.01; ***, P < 0.001.

Mentions:
Stinging insects in the genera vespula (wasp) and apis (bee) generate a local intradermal inflammatory response. To investigate a possible role of CD1, we obtained CD3+ T cells from healthy adult individuals and mixed them with wasp venom-treated and irradiated K562-CD1 APCs, which were mock transfected or transfected with either CD1a, CD1b, CD1c, or CD1d. As expected based on prior work (de Jong et al., 2014), we observed low but detectable alloreactive background responses of ∼1 in 2,000 T cells after 12–14 d in culture to mock-transfected target cells in donor C1175 (Fig. 1 A, left), which is representative of three donors. In the absence of venom, T cells showed responses to K562-CD1a cells at rates higher than to mock transfected cells or cells expressing other CD1 isoforms, confirming the presence and relatively high rates of CD1a autoreactive T cells seen previously (de Jong et al., 2010, 2014; de Lalla et al., 2011). Further, polyclonal responses to wasp venom above background levels were detected, but were seen only when using CD1a-expressing cells as targets (P < 0.05, Fig. 1 A, left, representative of three donors). These responses demonstrate that a T cell response to wasp venom is restricted by CD1a proteins.

fig1: Vespula spp and Apis mellifera venoms induce a preferential activation of CD1a-restricted T cells among the group1-CD1 reactive cells. (A) T cells were isolated by CD3 MACS beads from healthy donor PBMCs and cultured for 12–14 d with IL-2 and irradiated K562 cells transfected with CD1a (K562-CD1a), CD1b (K562-CD1b), CD1c (K562-CD1c), CD1d (K562-CD1d), or an empty vector (K562) in the presence of venom. CD1 reactivity was then examined by IFN-γ ELISpot with transfected or untransfected K562 cells either in the presence or absence of Vespula spp or Apis mellifera venoms. Representative data for one donor (C1175) of three are shown. (B) The CD1a-restricted T cell response in the presence or absence of anti-CD1a (donor C1098) and Vespula spp and Apis mellifera venoms. CD1a-restricted, venom-specific responses were measured in 21 donors for Vespula spp venom (C) and Apis mellifera venom (D). mDC or in vitro LC–like cells derived from CD14+ cells were pulsed with 1 µg/ml wasp venom (E) or bee venom (F) and incubated with the T cells in the presence or absence of anti-CD1a antibody or isotype control. IFN-γ production was measured by IFN-γ ELISpot. Representative data for one donor (C556 [E] and C560 [F]) of three are shown. Data were mean of triplicate measurements ± SEM. *, P < 0.05; **, P < 0.01; ***, P < 0.001.

Mentions:
Stinging insects in the genera vespula (wasp) and apis (bee) generate a local intradermal inflammatory response. To investigate a possible role of CD1, we obtained CD3+ T cells from healthy adult individuals and mixed them with wasp venom-treated and irradiated K562-CD1 APCs, which were mock transfected or transfected with either CD1a, CD1b, CD1c, or CD1d. As expected based on prior work (de Jong et al., 2014), we observed low but detectable alloreactive background responses of ∼1 in 2,000 T cells after 12–14 d in culture to mock-transfected target cells in donor C1175 (Fig. 1 A, left), which is representative of three donors. In the absence of venom, T cells showed responses to K562-CD1a cells at rates higher than to mock transfected cells or cells expressing other CD1 isoforms, confirming the presence and relatively high rates of CD1a autoreactive T cells seen previously (de Jong et al., 2010, 2014; de Lalla et al., 2011). Further, polyclonal responses to wasp venom above background levels were detected, but were seen only when using CD1a-expressing cells as targets (P < 0.05, Fig. 1 A, left, representative of three donors). These responses demonstrate that a T cell response to wasp venom is restricted by CD1a proteins.